KAGUYA is a Japanese Space Agency (JAXA) lunar orbiter mission. KAGUYA is named for Kaguya-hime (Princess Kaguya), a visitor to Earth from the Moon in a 10th century Japanese folk tale "Taketori Monogatari" (The Tale of the Bamboo Cutter) and was formerly called SELENE (SELenological and ENgineering Explorer).

The primary objective of the mission was a global survey of the Moon, as well as obtaining data on elemental abundance, mineralogical composition, topography, geology, gravity and the lunar and solar-terrestrial plasma environments. This mission served as an engineering test for future deep space missions.

The mission consists of three satellites, an orbiter containing most of the scientific equipment, a VLBI (Very Long Baseline Interferometry) Radio (VRAD) satellite named Ouna and a relay satellite named Okina designed to receive a doppler ranging signal from the orbiter when it is around the far side of the Moon and transmit the signal to Earth in order to estimate the far-side gravitational field.

KAGUYA launched 14 September 2007 on an H-IIA rocket from Tanegashima Space Center. Separation of the spacecraft from the launch vehicle occurred 45 minutes and 34 seconds after launch. KAGUYA deployed its solar panels and high-gain antenna, and completed two orbital maneuvers, the last on 17 September to put it into a 924 x 232,731 km Earth orbit with a period of 4 days, 23 hours and 33 minutes. After three more correction maneuvers, a lunar transfer trajectory injection burn was conducted. KAGUYA carried out its first lunar orbit injection at 21:20 UT on 3 October (6:20 a.m. October 4 JST) and entered a 101 x 11,741 km lunar orbit with a period of 16 hours, 42 minutes. The spacecraft made 6 orbit-transfer maneuvers to lower the orbit to a 118 minute, 80 x 128 km polar science orbit by 19 October. During the transition to lower orbit, the relay satellite Okina was released into a 100 km x 2,400 km polar orbit on 9 October at 00:36 UT and the VRAD satellite Ouna was released into a 100 x 800 km orbit at 04:28 UT on 12 October. Normal operations from orbit for the KAGUYA spacecraft started on 20 October.

KAGUYA concluded a successful two year mission of lunar exploration with a planned impact on the lunar surface. The impact plume was observed by Earth-based telescopes.